Nov. 5, 1959
IXFRARED AND VISIBLE SPECTRA OF GASEOUS B2S3
However, the phenyl substituents on the boron seem to have a lessened attraction for the pair, as indicated by the structures
TABLE I11 INFRARED ABSORPTIONOF THE B-S BOSD OF SOMEAMINOBORANES Compound
The B-N double bond character of I, therefore, is somewhat stronger than in (ethylpheny1amino)diethylborane (11)) where the boron-attached alkyl groups do not produce such a degree of electron delocalization on the B-N bond. Further weakening of the double bond character appears in dichloro-(dipheny1amino)-borane (III), though the difference between I1 and I11 is not as great as expected. Presumably the N-attached phenyl rings in the latter case are not both coplanar with the rest of the molecule,6 otherwise two of the ohydrogens of the phenyl groups would constitute steric hindrance. The planarity is likely to be distorted thus affording a decrease of resonance which demonstrates why the second phenyl group on the nitrogen does not produce as much weakening of the B-N double bond character as one might expect.
[CONTRIBUTIOS FROM THE
DEPARTMEST OF
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(Monopheny1amino)-dimet hyl borane6 Dimethyl-( pyrro10)-borane5 (Methylnaphthy1amino)-dimethylborane Dichloro-(diphenylamino)-borane5 (Ethylpheny1amino)-diethylborane (Ethylpheny1aniino)-diphenylborane (Di-sec-buty1amino)-diethylborane Dichloro-(diethylamino)-boranel ( Amino)-dimethylborane8 Dichloro-(dimethylamino)-boraneg ( Dimethylamino)-dimethylborane8
Absorption, cm. -1
1330 1343 1370 1378 1408 1424 1459 1505 1515 1526 1530
The influence of substituents on the stability and bond characteristics of the B-N linkage of aminoboranes is under further investigation; the findings will be published later. Acknowledgment is accorded to the Schwarzkopf Xicroanalytical Laboratory, Woodside 77, New York, for analyses reported herein. (8) H. J. Becher and J. Goubeau, Z . anoug. allpem. Chem , 268, 133 (19523. (9) J. Goubeau, L l . R a h t z a n d H. J. Becher, zbrd., 275, 161 (1954).
DURHAM, SORTH CAROLINA
CHEMISTRY, vXIVERSITY OF !vISCO,I'SIN]
Infrared and Visible Spectra of Gaseous BSSB at High Temperatures1 BY FRANK T. GREENEAND JOHN L. MARGRAVE RECEIVED JUNE 1, 1959 Infrared emission and absorption spectra of gaseous B2S3 have been observed for the normal isotopic mixture and for a sample prepared with Bl0. Examination of t h e isotope shifts with the aid of the Redlich-Teller product rule gives support t o a twisted zigzag model for BPS3 with CPsymmetry. Electronic absorption spectra were observed in the regions 5400-7200 k.,3900-4200 A , , and 3100-3500 k .
During the past few years considerable attention has been given to the determination of the fundamental properties ol' B203.* Its sulfur analog, B&, has, however, been neglected almost entirely. Infrared Studies of Gaseous B&.--Xn infrared spectroscopic investigation of gaseous B2S3 has been made over the range 600-1000". For this work, B& was prepared by passing dried H2S through amorphous boron a t 700" and collecting the vaporized product on a cold finger. The resulting product contains ms?,B2S3 and some sulfur and boric acid impurity. Single crystals? apparently of HBS2, have been prepared and are being studied This mixture was introduced directly into a 1-inch quartz or Vycor tube t o which suitable windows were attached a n d heated in z'acuo at 300 and 600' for several hours until degassed and all H2S removed. At the higher temperatures there was considerable condensation of vaporized material as a white smoke in cool portions of the tube and usually about 100 mm. of dry argon was introduced to prevent boiling and retard diffusion just before the temperature was raised to t h a t of a run. (1) Presented before t h e 135th Meeting, American Chemical Society, Boston, April, 1959. ( 2 ) (a) D. A. Dows a n d R. F. Porter, THISJ O U R N A L , 78, 5105 (1956); (b) D. W h i t e , P. N. Walsh a n d D . E. iMann, J . Chem. Phys., 28, 508 (1958); ( c ) E. PI'. Lotkova, V . V. Obukhov-Denisov, N. N. Sobolev a n d V. P. Cheremicinov, O p f k s a i d Spectroscopy (Russiaiz). 1, 772 (195(i), 3 , 5CiO (lCI57); ( d ) 1%'. Taylor, J . ( ' h e n . P h ) s . , 28, 6 2 5 (19%).
The spectrum of the gas over B2SS was examinrd in emission and absorption in the region 10,000 to 400 cni.-' with a Beckman Model I R 2 spectrometer. The sourcc' h using was separated about 1 meter from the entrance optics and a 12-inch nichrome furnace containing a quartz or Vycor tube with KRr windows was inserted. For emission studies with this instrument, a n external chopper which could be synchronized with the synchronous rectifier was mounted in front of the entrance optics. For the longer wave length region, a Perkin-Elmer Model 112 double pass spectronieter with a CsBr prism was used in emission out to 300 cm.-1. For emission work, a series of diaphragms was used to mask out wall radiation. Several tracings were made for each spectral region studied a t a variety of temperatures and with a number of different samples. Five bands were observed both in emission and absorption. Their maxima were a t 1322, 990, 919, 859 and 602 cm.-l. When boron containing 95%, Bl0 was substituted for the normal isotopic mixture, the bands were observed to shift to 1389, 1040, 952, 906 and 605 cm.-'. This isotope shift is probably too small as a result of the overlapping of Bl0-B1l bands with Bl1-B1l bands; correction for this effect indicates net isotope shifts o f 71, 54, 37, 51 and 6 cm.-', respectively.
There are several chemically plausible models for B2S3: a linear molecule (Dall), a bipyramid (D3!,), a plane V or W-shaped molecule (CS,.) or a twisted zigzag ((2,). Ah upper limit for the isotope shift permitted for a given model can be calculated
hl. J. SIENKO
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VOl. s1
from the Redlich-Tellcr product rule3 since this rule gives the product of the ratios of the frequencies of the isotopically substituted niolecules for each vibrational frequency and since the frequency must remain the same or increase on substitution of a lighter isotope. The observed frequency ratios for the isotopic molecules are
require violation of classical valences, have been tentatively rejected. If the Cz model is correct, there should be nine infrared active fundamentals of which only five have been observed. The remaining four frequencies almost certainly belong to weaker bending modes and might be below the limit of detectability.
1389/1318 = 1.053 1010/980 = 1.050 952/915 = 1.040 906/855 = 1.060 605/599 = 1.010
Visible and Ultraviolet Spectra of B2S3.-The electronic spectrum of the gas over B ~ S aJ t 1000° was investigated in absorption from 3000 to 7400 A. with a Bausch and Lomb 1.6 meter grating A No. 2 photoflood and a xenon arc were used as light sources. Bands were obstrved in the regions 5400-7200, 39004200 and 3100-3500 A . Tlie red band system bears a t least a superficial resemblance to the green system of BsOa.
If the frequencies observed are ~~undamentals of
B&, then i t can be shown that the D,t, and Dmf, structures are inconsistent with the observed shifts. The C2\.point group is not eliminated directly by the product rule. However, the most plausible assignment of the observed frequencies seems to favor the CZstructure as the only chemically sound structure which is consistent with the observed isotope shifts. Other models, which (8) G . I-IerLberg. “Infrared and Rariian Spectra.” 11. Van Nostrand Co., Inc., S e w York, N.Y.,1 9 5 .
[cO\ r R I l J L I I U \ I RORI 1 I I F
Acknowledgment.-This work was in part supported by the Callery Chemical Company under a contract from the Bureau of Aeronautics, Department of the Navy. MADISON, WISCONSIX
BAKERL A U O R A r O R Y
OE CEIEMISTRY, CORUELL UNIVERSITY]
Thallium-Tungsten Bronze : A Solid State Defect Structure1 BY A I . J. SIENKO RECEIVED APRIL 29. 1969 Thallium-tuiigsteti bronzes, Tlz\V03, have been prcp:rred ranging in composition from x = 0.19 to x = 0.36. Preparation methods included: (1) heating T l ~ n ‘ O ~ , Li’O:$ and W ; ( 2 ) vapor phase reaction of T1 and WOa; (3) electrolysis of TlzC03 Znri 1 ’03mixtures. Prnducts were crystallinc and powder diagrams could be indexed in the tetragonal system with a = I .31 and’c = 12.50 A . Electrical resistance 1ne;tsurements using a potential probe method on single crystals indicated inctallic conduction with specific resistivity varying from 0.0 X l o w 3ohiri-cm. a t 25’ t o 9.0 X ohm.cm. at 240”. Thermoelectric power a t rnoiri temperature was -20 microvolts per degree referred to platinum, suggesting one free electron per thallium atom. A general model is proposcd for the tungsten bronzes M,\\‘Os where M is viewed as giving rise t o local energy levels in the forbidden gap between the conduction and valence bands of OS.
1.
The tungsten bronzes,2hl,IVO3, in which M is a univalent metal and x lies between 0 and 1, represent an unusually interesting series of non-stoichiometric materials with properties ranging from metallic to semi-conducting depending on what M is. If h l is sodium, the resulting sodium-tungsten bronze shows a linear increase of resistance with temperature and a Hall coefficient corresponding to one free electron per sodium atom3; if hl is copper or silver, the resulting tungsten bronze shows an exponential decrease of resistance with rising t e m p e r a t ~ r e . ~I n both cases, magnetic susceptibility is low and independent of temperature. I n attempting to set up a general model to account for these observations, we have been led to reject the older view of pI‘Iz\VOa as a solid solution of WOa in hypothetical M W 0 3 in favor of a model in which ?rl,b’O~ is viewed as a solid solu(1) T h i s research mas supported in whole or in p a r t by t h e United S t a t e s Air Force under Contract No. A F 19(ti38)-101 monitored b y t h e AP Office of Scientific Research of t h e Air Research arid Development Command. ( 2 ) S e e , fc,r ex,Ltuple, ti. I I i g f i , %. p h y s i k . C h e m . , B29, 1!1% ( 1 5. Straumanis a n d S. S. Hsu, THISJ O I I K N A L , 72, 4027 (1 lagneli a n d R. nlomberg, Acta Chum. Scand.. 5 , 377 ( 1 Conrijv , ~ i ! < l‘1 I
